I've been enjoying thinking up possible responses to the "But you have a husband" line...
Yes, and he has a wife. (beandip)
Yes, and I had a prior commitment. (beandip)
Raise an eyebrow; a moment of complete silence, beandip. You could even make it an obvious beandip, like "How about those, um... Broncos?"
Oh! (slightly horrified) You mean, you don't
? (tiny pause) Oh, I'm sorry, your marital status is none of my business! (beandip)
Yes, (sarcastically) and I have to be home every day
in time to bring him the paper, mix him a drink, and change the TV to his favorite channel! (beandip)
...Now that I'm through being silly - the point is to come up with a "Toots Special," and just repeat it every time.